package com.lagou.client;

import com.alibaba.fastjson.JSON;
import com.lagou.encoder.RpcEncoder;
import com.lagou.handler.UserClientHandler;
import com.lagou.pojo.RpcRequest;
import com.lagou.serializer.JSONSerializer;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.string.StringDecoder;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.UUID;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class RPCConsumer {
    // 1.创建一个线程池对象  -- 它要处理我们自定义事件
    private static ExecutorService executorService =
            Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());

    // 2.声明一个自定义事件处理器  UserClientHandler
    private static UserClientHandler userClientHandler;

    // 3.编写方法,初始化客户端  ( 创建连接池  bootStrap  设置bootstrap  连接服务器)
    private static void initClient() throws InterruptedException {
        //1) 初始化UserClientHandler
        userClientHandler = new UserClientHandler();
        //2)创建连接池对象
        EventLoopGroup group = new NioEventLoopGroup();
        //3)创建客户端的引导对象
        Bootstrap bootstrap = new Bootstrap();
        //4)配置启动引导对象
        bootstrap.group(group)
                //设置通道为NIO
                .channel(NioSocketChannel.class)
                //设置请求协议为TCP
                .option(ChannelOption.TCP_NODELAY, true)
                //监听channel 并初始化
                .handler(new ChannelInitializer<SocketChannel>() {
                    protected void initChannel(SocketChannel socketChannel) {
                        ChannelPipeline pipeline = socketChannel.pipeline();
                        pipeline.addLast(new RpcEncoder(JSON.class, new JSONSerializer()));
                        pipeline.addLast(new StringDecoder());
                        pipeline.addLast(userClientHandler);
                    }
                });
        //5)连接服务端
        bootstrap.connect("127.0.0.1", 8999).sync();
    }

    // 4.编写一个方法,使用JDK的动态代理创建对象
    // serviceClass 接口类型,根据哪个接口生成子类代理对象;   providerParam :  "UserService#request#"
    public static Object createProxy(Class<?> serviceClass) {
        return Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(),
                new Class[]{serviceClass}, new InvocationHandler() {
                    public Object invoke(Object o, Method method, Object[] objects) throws Throwable {
                        // 1)初始化客户端client
                        if (userClientHandler == null) {
                            initClient();
                        }
                        // 2)封装rpcRequest
                        RpcRequest rpcRequest = new RpcRequest();
                        String requestId = UUID.randomUUID().toString();
                        System.out.println("requestId:" + requestId);
                        String className = method.getDeclaringClass().getName();
                        String methodName = method.getName();
                        Class<?>[] parameterTypes = method.getParameterTypes();
                        rpcRequest.setRequestId(requestId);
                        rpcRequest.setClassName(className);
                        rpcRequest.setMethodName(methodName);
                        rpcRequest.setParameterTypes(parameterTypes);
                        rpcRequest.setParameters(objects);
                        String requestString = JSON.toJSONString(rpcRequest);
                        System.out.println("requestString:" + requestString);
                        userClientHandler.setParam(JSON.parseObject(requestString));
                        // 3).使用线程池,开启一个线程处理处理call() 写操作,并返回结果
                        return executorService.submit(userClientHandler).get();
                    }
                });
    }
}
